Team SpotTeam SpotCooperative Light Finding RobotsCooperative Light Finding Robots

A Robotics Academy Project

Louise Flannery, Laurel Hesch, Emily Mower, and Adeline Sutphen

Under the direction of:Professor Chris Rogers

Tufts University , Fall 2003

Team Spot: MotivationTeam Spot: MotivationThe RobotableThe Robotable

The Robotable combines virtual and real world objects, The Robotable combines virtual and real world objects, allowing users to communicate and manipulate each allowing users to communicate and manipulate each other’s robots in a real time environment.other’s robots in a real time environment.

A table similar Tufts Robotable is in development at A table similar Tufts Robotable is in development at Lincoln University in Christchurch, New Zealand.Lincoln University in Christchurch, New Zealand.

Team SpotTeam SpotProject GoalProject Goal

Develop a team of mobile Develop a team of mobile autonomous robots that, within the autonomous robots that, within the boundary of the Robotable, will boundary of the Robotable, will locate and travel to a spot of bright locate and travel to a spot of bright light.light.

To relate the project to children To relate the project to children through education outreach through through education outreach through the CEEO and Tufts Department of the CEEO and Tufts Department of Child Development.Child Development.

Design ConstraintsDesign Constraints

The robots must be autonomousThe robots must be autonomous No central processing unit.No central processing unit.

The robots must fit onto the RobotableThe robots must fit onto the Robotable Must be small enough to maneuver Must be small enough to maneuver

around the table.around the table. The stationary robots must determine The stationary robots must determine

the position of the light and verify it the position of the light and verify it using a mobile robot and to report using a mobile robot and to report that position to the user.that position to the user.

Design Idea: TriangulationDesign Idea: Triangulation

3 Robots (2 Stationary, 1 Mobile)3 Robots (2 Stationary, 1 Mobile) The two stationary robots will scan 90 degrees and determine the The two stationary robots will scan 90 degrees and determine the

position within the scan at which the the greatest light intensity was position within the scan at which the the greatest light intensity was found.found.

They will send this position to the mobile robot They will send this position to the mobile robot The mobile robot uses this position to determine its movement pattern.The mobile robot uses this position to determine its movement pattern. The mobile robot then travels to the identified location.The mobile robot then travels to the identified location.

St.

St.

M

Design Idea: Sliding Design Idea: Sliding ArmsArms

3 Robots (2 Robotic Arms, 1 Mobile Robot)3 Robots (2 Robotic Arms, 1 Mobile Robot) Robotic Arms start at (0,0) and advance out, along their specific Robotic Arms start at (0,0) and advance out, along their specific

sides- the x and y axis of the RoboTable.sides- the x and y axis of the RoboTable. The arms locate the x and y coordinates with the greatest light The arms locate the x and y coordinates with the greatest light

intensity and send the information to the mobile robot.intensity and send the information to the mobile robot. When the mobile robot has found the light spot, it reports its When the mobile robot has found the light spot, it reports its

coordinates.coordinates.

ARM

ARM X

Y

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Design Idea: Quadrant Design Idea: Quadrant SystemSystem

4 Mobile Robot System4 Mobile Robot System The Mobile robots will determine which quadrant has the light spot.The Mobile robots will determine which quadrant has the light spot. This quadrant will be subdivided into 4 quadrants.This quadrant will be subdivided into 4 quadrants.

The within the specified quadrant mobile robot will move to the corner of its new sub-quadrant The within the specified quadrant mobile robot will move to the corner of its new sub-quadrant and determine which sub-quadrant holds the light spot.and determine which sub-quadrant holds the light spot.

The other robots will move to positions on the edge of their quadrants closest to the spot of The other robots will move to positions on the edge of their quadrants closest to the spot of lightlight

The mobile robots will repeat this process until one converges on the light The mobile robots will repeat this process until one converges on the light spot.spot.

Once again, upon completion the mobile robot will report its coordinates.Once again, upon completion the mobile robot will report its coordinates.

LightSpot

M4

M1

M2

M3

Prototype: The Spot Prototype: The Spot FinderFinder

Lego prototype.Lego prototype. Triangulation methodTriangulation method RCX IR communicationRCX IR communication

SuccessesSuccesses Found the position of the Found the position of the

light using triangulation.light using triangulation. Developed programming Developed programming

methods for combining methods for combining and processing data and processing data between multiple robotsbetween multiple robots

Areas of ImprovementAreas of Improvement Need for more sturdy Need for more sturdy

robots.robots. Limited range with IR Limited range with IR

communication communication Lego rotation sensor Lego rotation sensor

unreliable for find the unreliable for find the position of the light.position of the light.

Prototypes: Lego RobotsPrototypes: Lego Robots

Original Mobile Robot

Original Stationary Robot

Flow Chart of Flow Chart of FunctionalityFunctionality

Stationary robots scan for brightest light position.

The position of the greatest spot is transmitted via IR to the mobile robot.

Mobile robot reads in light value

Interprets value using a lookup table

Mobile Robot moves to correct position

Electrical ComponentsElectrical Components

There are three main electrical There are three main electrical modules:modules: Infrared CommunicationInfrared Communication Motor ControlMotor Control Light SensingLight Sensing

These three modules were These three modules were coordinated using the OOPic-R coordinated using the OOPic-R Microprocessor.Microprocessor.

OOPic-R MicroprocessorOOPic-R Microprocessor

This microprocessor uses object oriented This microprocessor uses object oriented programming in Basic, which simplifies programming in Basic, which simplifies the programming process.the programming process.

The chip includes 31 I/O pins and The chip includes 31 I/O pins and additional voltage sources for device additional voltage sources for device interface.interface.

The microprocessor’s voltage source was The microprocessor’s voltage source was used for IR communication, the Liquid used for IR communication, the Liquid Crystal Display (LCD), and the photo-Crystal Display (LCD), and the photo-resistor circuits.resistor circuits.

Light SensingLight Sensing

A simple photo-resistor was placed A simple photo-resistor was placed in series with a resistor to register in series with a resistor to register values of light. values of light.

This was inputted to the This was inputted to the microprocessor using the analog to microprocessor using the analog to digital converterdigital converter

This module’s accuracy is hampered This module’s accuracy is hampered by ambient light spots that are by ambient light spots that are brighter than the light being sought.brighter than the light being sought.

IR CommunicationIR Communication While infrared communication is currently While infrared communication is currently

functional, it is inaccurate over long distances.functional, it is inaccurate over long distances. High speed serial communications functionality High speed serial communications functionality

was abandoned due to a high degree of was abandoned due to a high degree of inaccuracy.inaccuracy.

Currently, the stationary robots send infrared Currently, the stationary robots send infrared pulses corresponding to the position of brightest pulses corresponding to the position of brightest light.light.

The Mobile Robot interprets the number of pulses The Mobile Robot interprets the number of pulses sent to determine the stationary robot position.sent to determine the stationary robot position.

This was the most problematic module in this This was the most problematic module in this project.project.

Motor ControlMotor Control

The microprocessor controls the servo The microprocessor controls the servo motors for both the mobile and stationary motors for both the mobile and stationary robots. robots.

The servos have highly variable torque, The servos have highly variable torque, which makes the mobile robot veer to which makes the mobile robot veer to one side and the stationary robots have one side and the stationary robots have slightly variant positional rotation. slightly variant positional rotation.

The motion is calculated looking a look-The motion is calculated looking a look-up table using the IR received value as up table using the IR received value as inputs.inputs.

Motor Controller:Motor Controller: Look-Up Table Look-Up Table

Mobile RobotMobile Robot

Powered by 2 Servo Powered by 2 Servo Motors Motors

Controlled with the Controlled with the OOPIC-R OOPIC-R microcontrollermicrocontroller

IR receiverIR receiver Liquid Crystal DisplayLiquid Crystal Display

Stationary RobotStationary Robot

Light sensor Light sensor rotates atop a DC rotates atop a DC servo motorservo motor

Controlled by Controlled by OOPIC-R OOPIC-R microcontrollermicrocontroller

IR transmittersIR transmitters

Team Spot In ActionTeam Spot In Action

Team Spot in ActionTeam Spot in Action

Team Spot WebpageTeam Spot Webpage

Child Development Child Development ObjectivesObjectives

Learn about the engineering process and the Learn about the engineering process and the science and technology content of each Team’s science and technology content of each Team’s robotics challenge. robotics challenge.

Help engineers think about how to communicate Help engineers think about how to communicate and adapt their knowledge for peers without and adapt their knowledge for peers without their engineering background and for children.their engineering background and for children.

Synthesize and adapt main concepts from team Synthesize and adapt main concepts from team projects appropriately for a 4projects appropriately for a 4thth-6-6thth grade robotics grade robotics curriculum.curriculum.

Implement this curriculum as an after-school Implement this curriculum as an after-school enrichment program in Spring 2004.enrichment program in Spring 2004.

Evaluate the process of making complex Evaluate the process of making complex technology accessible to children.technology accessible to children.

Course StructureCourse Structure

Day of IntroductionDay of Introduction 3 Main Phases: 3 Main Phases: Mobile robotsMobile robots Stationary robotsStationary robots Integrative final project-Treasure Integrative final project-Treasure

IslandIsland Analysis of curriculumAnalysis of curriculum

Team Spot: The FutureTeam Spot: The Future

IR will be replaced with blue tooth IR will be replaced with blue tooth technology.technology.

Implementation of the multiple spot and Implementation of the multiple spot and moving spot problems.moving spot problems.

Development of more accurate methods of Development of more accurate methods of scanning through 90-degrees (stationary scanning through 90-degrees (stationary robot).robot).

Development of method for altering the Development of method for altering the inequality of the mobile robot servo motors.inequality of the mobile robot servo motors.

CEEO after-school workshops in Spring 2004.CEEO after-school workshops in Spring 2004.